MOSCOW—The public airing of a dossier Tuesday on President-elect Donald Trump casts a spotlight on Russia’s dark art of kompromat, the practice of collecting compromising material on prominent individuals for the purposes of blackmail.

The dossier is packed with unverified allegations, including a claim that Russian officials obtained...

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President-elect Donald Trump says allegations made about him in an unverified dossier prepared by ex-British intelligence officer, Christopher Steele, are completely fabricated. WSJ’s Jason Bellini breaks down what we know about the material and the person behind it. Photo: Getty.